<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>todo list</h1>
<input id="todo_input" type="text" placeholder="请输入"></input>
<button onclick="add_todo()">添加</button>
<ul id="list"></ul>
<script src="todo.js"></script>
</body>
</html>